Coast (2024)

If you've ever been to the beach, you've been on a coast. The

coast

is the land along a sea. The boundary of a

coast

, where land meets water, is called the coastline.

Waves, tides, and currents help create

coastlines

. When

waves

crash onto shore, they wear away at, or erode, the land. But they also leave behind little parts of the sea, such as shells, sand dollars, seaweeds, and hermit crabs. Sometimes these objects end up as more permanent parts of the

coastline

.

Coastal

changes can take hundreds of years. The way

coasts

are formed depends a lot on what kind of material is in the land and water. The harder the material in the land, the harder it is to

erode

.

Coastlines

of granite, a hard rock, stay pretty stable for centuries. Sugarloaf Mountain, on the

coast

of Rio de Janeiro, Brazil, is made mostly of

granite

and quartz. It has been a landmark for centuries.

The famous White Cliffs of Dover, in England, are made of calcium carbonate. This is a soft material and

erodes

easily. However, it exists in such great quantities that years of erosion have not made a visible impact on the

coastline

. The White Cliffs are a landmark of the English

coast

of the English Channel. (The other

coast

is French.)

The sandy

coastlines

of islands, on the other hand, change almost daily. The

island

of Mont Saint Michel is only an

island

when the

tide

is in. It is part of the

coast

of France during low tide.

Islands

are also the site of Earth's newest coastlines, like a Tongan

island

created in March 2009 by the eruption of the volcano Hunga Tonga-Hunga Haapai. The "Big

Island

" of Hawaii, created by five volcanoes, sometimes expands its

coastline

when one of its active volcanoes, Mauna Loa or Kilauea, erupts. If lava flows reach the ocean, the lava cools and forms new

coastline

along the Pacific Ocean.

Tides

, the rise and fall of the ocean, affect where sediment and other objects are deposited on the

coast

. The water slowly rises up over the shore and then slowly falls back again, leaving material behind. In places with a large tidal range (the area between high tide and

low

tide

,)

waves

deposit material such as

shells

and

hermit crabs

farther inland. Areas with a low

tidal range

have smaller

waves

that leave material closer to shore.

Waves

that are really big carry a lot of energy. The larger the

wave

, the more

energy

it has, and the more

sediment

, or particles of rock, it will move.

Coastlines

with big

beaches

have more room for

waves

to spread their

energy

and deposits.

Coastlines

with small, narrow

beaches

have less room for

waves

to spread out. All the

waves

'

energy

is focused in a small place. This gives the small

beaches

a tattered, weathered look. Sandy

beaches

are washed away, and rocky

coastlines

are sometimes cracked by strong

waves

.

Because

coasts

are dynamic, or constantly changing, they are important ecosystems. They provide unique homes for marine plants, animals, and insects.

Coasts

can be icy, like the Shackleton

Coast

of Antarctica, or desert, like the Skeleton

Coast

of Namibia.

Coasts

help us understand natural events, such as weather and changing sea levels. During storms,

coasts

are the first places to be flooded. Some

coasts

have coastal plains.

Coastal

plains

are pieces of flat, low-lying land that can become visible when

sea levels

start decreasing.

Coasts

, as beautiful as they tend to be, have it rough sometimes. They are affected by pollution, oil spills, and garbage from both land and sea.

Pollution

negatively affects the way a

coast

looks and is damaging to the

marine

life that lives there.

People visit the

coast

on vacation to participate in activities like fishing, boating, and swimming.

In the United States,

coasts

can be a reference to culture as much as physical geography. For example,

West

Coast

people in California identify with a different type of

culture

, or way of life, than East Coast residents in New York City or Washington, D.C. The southern Gulf Coast of New Orleans, Louisiana, has yet a different cultural association.

This cultural connection to the

coast

shows up in many different ways, including food and leisure activities. Residents of the

Gulf

Coast

, for instance, are more familiar with food made from shrimp, a seafood native to the warm waters of the Gulf of Mexico. Maine, on the northern

East

Coast

, is famous for its lobster.